RAID 1 Degraded -- need advice -- Please help!

[pfleischman]

I have a simple mirrored raid setup (just two 1TB drives) with a 1TB Time Machine Drive. I ran Repair Disk Permissions last night and then shut down (Onyx told me to after it scanned my startup volume).

Today I unplugged my MacPro (it was already off) to plug in another computer for a few min, and when I brought it back up it took a while to boot so I went into disk utility and it started rebuilding the RAID.

Why all of a sudden would this happen? I am worried, because this computer is my livelihood. The Time Machine Drive is up-to-date, so i'm not sh*ting my pants right now. Any recommendations on backing up hundreds of gigs of photos? I was thinking of getting a Blue Ray burner.

 

[brisbaneguy29]

I have had this happen twice now.
I have 2 x 1TB external WD My Book drives in simple mirror RAID, and twice now I have opened disk util, and it has said the RAID was degraded. The machine then proceeded to rebuild the RAID for the next 3 days.

At the end all data was intact, lost nothing, and I was able to still use the drives during the rebuild.

 

[brendon2020]

sometimes the raid will break and it could be the drive, but opening up diskutil has always fixed the issue for me. Sometimes i would have to boot off the leopard disk and run diskutil that way.

 

[NoNameBrand]

What does the SMART status say?

I've had a problem on a Linux box relating to a MD RAID1 set falling apart every boot. For some reason it hadn't written the set's ID string to the superblock of the disk that was being dropped.

That said, I have no idea how Mac OS X's software RAID works.